Apple officially announces a tool to dual boot Intel-based Macs with Windows XP.

All the hacking to run Windows XP on Macs is unnecessary now. Currently Boot Camp is available as free download and is still in beta.
Boot Camp will be a feature in "Leopard," Apple's next major release of Mac OS X that will be previewed at Apple's Worldwide Developer Conference in August.
You can download the beta of Boot Camp on the Apple site.

The availability of Boot Camp does not mean that Apple plans to support Windows. Apple says they just reacted to customer demand.

System Requirements for Boot Camp are an Intel-based Mac with a USB keyboard and mouse, or a built-in keyboard and TrackPad; Mac OS X version 10.4.6 or later; the latest firmware update; at least 10GB of free space on the startup disk; a blank recordable CD or DVD; and single-disc version of Windows XP Home Edition or Professional with Service Pack 2 or later.
More details in this Apple press-release.